In system Management, we are creating users. what is the purpose of creating those users and how they could access the APIs that are created?

These are dashboard users that can edit and manage the configurations for your APis

If you want to give users access to APIs you must create a token using the API Keys functionality, or if you want to associate an identity with a token you must create a developer.

You must then create . anew key request from the developer to a policy object and approve it (this i the portal flow). There isn’t a direct way in the dashboard to create a user and add tokens yet, you must either just create tokens or use the portal.